ApiUrl           = "https://7105.api.greenapi.com";
    MediaUrl         = "https://7105.media.greenapi.com";
    IdInstance       = "71051...";
    ApiTokenInstance = "425010d90e114aa6b78f0969e...";

    GroupID = "120363403182713241@g.us";
    UserID  = "123123123@c.us";

    AccessParameters = OPI_GreenAPI.FormAccessParameters(ApiUrl, MediaUrl, IdInstance, ApiTokenInstance);
    Result           = OPI_GreenAPI.AddGroupMember(AccessParameters, GroupID, UserID);